On the chromatic numbers of signed triangular and hexagonal grids

A signed graph is a simple with two types of edges. Switching vertex v corresponds to changing the type each edge incident v. homomorphism from G another H mapping φ:V(G)→V(H) such that, after switching any number vertices G, φ maps every an same in H. The chromatic χs(G) order smallest that there We show triangular grids at most 10 and hexagonal 4.